An effective scaling frequency factor method for harmonic vibrational frequencies: The factors’ transferability problem

Performance of the so-called effective scaling frequency factor method, ESFF, for scaling of harmonic theoretical frequencies is analyzed and compared with the well-known SQM method. A training set of 30 molecules (660 experimental frequencies) has been used to optimize a set of 11 scaling factors. Results point towards somewhat lower RMS deviation with respect to the experimental values obtained with ESFF method, as well as a better transferability of ESFF scaling factors, what allows to think of this method as an alternative to SQM, at least as far as frequencies are concerned.